System for sound transmission



I. H. HAMMOND, IR.

SYSTEM FOR SOUND TRANSMISSION. APPLICATION FILED JUNE 7. I917. RENEWEDD50. 8, I92I.

1,425,522. Patented Aiig. 15, 1922.

Q I g s gunman N m 'awoenlfoz @51 M attozmq and a resident setts,

transmission system JOHN HAYS HAMMOND, JR, 0F GLOUCESTER, MASSACHUSETTS.

SYSTEM FOR SOUND TRANSMISSION.

Specification (if Letters Patent.

Application filed June 1917, Serial No. 173,331. Renewed December 8,1921. Serial No. 520,992.

T 0 all whom z'tmay concern:

Be it known that 1, JOHN HAYS HAM- MOND, Jr, a citizen of the UnitedStates, of the city of Gloucester, in the county of Essex and State ofMassachuhave invented a new and useful System for Sound Transmission, ofwhich the following is a specification.

Some of the objects of this invention are to provide an improvedmultiplex sound to provide a multiplex sound transmission system whichmay be controlled in response to electroradiant energy; and to provideother improvements, as will appear hereinafter.

in the accompanying drawing, Fig. 1 is a diagrammatic side elevationpartly in vertical section of a multiplex sound transmission systemconstructed in accordance with this invention; and Fig. 2 is adiagrammatic fragmentary side elevation of a modified form of the same.

Referring to the drawing, one embodirnent of this invention comprises aplurality of circuiar diaphragmslt), 11 and 12, which are arranged tocover circular openings provided therefor in a rigid wall or walls 15,which might be the exterior wall of the hull of a marine vessel, and inthat case the diaphragms might be arranged in horizontal alinementbeneath the surface of the surrounding water. These three diaphragms arearranged to be vibrated either separately or otherwise by threeelectrical oscillators 20, 21 and 22 of any suitable construction, theoscillators shown being of a well known construction, and eachcomprising an annular electromagnet 25 arrange to be energized by abattery 26 and a hollow cylindrical copper vibrator 27 which issurrounded by the magnet 25 and which is clamped securely between twoplates 28 which are fixedly secured upon a rod 29, one end of which isrigidly secured to the central portion of the corresponding diaphragm10, 11 or 12, and the other end of which is arranged to reciprocate in afixed bearing 30. Arranged loosely within the vibrator 27 is astationary cylindrical armature 35, which carries an insulated windingwhich is arranged in two coils 36 and 37 which are wound 'n oppositedirections. The armature coils 36 and 37 of the three oscillators 20. 21and 22 are in series respectively with three circuits 40, 41 and 42,which are enelgized respectively. by three electrical alternators 43, 44and 4L5,having predetermined different frequencies respectively. Thethree armature circuits 450, 4:1 and d2 are also arranged to beperiodically interrupted or broken respectively by three commutators 45,t6 and 47 which are rotated at uniform but different rates respectivelyto break up the Oscillations in the three circuits 10, &1 and 42, intothree series of groups of oscillations having different group irequencies respectively, the group frequency in each circuit being preferablyless than the frequency of the correspondin oscillator. 5

instead of having only a single commutatore'i' in any one or more of thearmature circuits, as for instance, circuit 12 two or more commutators47 may be placed in any one or more of these armature circuits as shownm Fig. 2, the several commutators being arranged to interrupt thecircuit at different regular rates. two commutators are used, as in Fig.2, the commutators would be so rotated as to break up the oscillationsin the circuit 42 into sets of groups of oscillations having a wavefrequency predetermined by the alternator 45. a group frequencypredetermined by one of the commutators 47, and a set frequencypredetermined by the other commutator 47. In this manner, acorresponding series of sets of groups of sound waves will betransmitted from the corresponding diaphragm 12, thus giving a triplefrequency and making the system more selective,

For controlling the three oscillators 20 21 and 22 selectively inresponse to electr 3 radiant energy, the three circuits 40, 41 and 42are arranged to be. controlled respectively by three oscillatbryswitches 50, 51 and 52, which are normally held open by springs 53, 54and 55. These switches 50,.

51 and 52 are arranged to be controlled respectively by three stationaryelectromag nets, 60, 61 and 62, which'are in three separate circuits 63,64 and 65, which are arranged to be energized respectively by three highfrequency electric alternators 66;; 67 and 68, and to be controlled in awell kndwn manner respectively'by three mercury vapor detectors 70, 71and 72, or other suitableidetectors, which arearranged in a well knownmanner to be selectively controlled by three closed oscillatory circuits7 5, 76 and 77. which are tuned to different frequencies re spectively,and which include respectively For instance, when three coils 78, 79 and80, and three variable condensers 81,82 and 83. The. three coils Avariable condenser 94 is shunted around the intermediate coil 92, andthe three coils 91, 92 and 93 are arranged in a circuit 95, which isarranged to be energized by a battery 96, and to be controlled in awellknown manner by a gaseous-detector 97 or other suitable detector, whichis arranged in a well known manner to be con trolled by a closedoscillatory circuit 98, which includes a coil 99,v and a variablecondenser 100, the'coi'l 99 forming the secondary of a transformer 105,which includes a prinrary coil 106 which is in series with an openaerial circuit or antenna- 110, which is grounded as at 111. The closedoscillatory circui; 98 which is controlled by the open aeriaz circuit110, is preferably tuned to the natural frequency of oscillation of theopen aerial circuit which may be for instance 1,000,000 per second, andthe three closed oscillatory circuits 75, 76 and 77 which control thethree mercury vapor detectors 7 0,"

71 and 72 are preferably tuned to different frequencies respectively,which are each lower than the frequency of the open circuit 110.

This improved system is arranged to be utilized in connection with anysuitable system, or systems. for the transmission of ra-' diant energy,whereby three series of electroradiant ingantenna 110, and the closedcircuit '98 controlled thereby, and "having three difi'erthe [closedcircuits 7 5,; 7 6' spon ing' to the threefrequenc'ies to which thethree mercuryvapor detectors "70, 71 and 72 are respective y tuned.

I In theoperation of this improved system,- 1 when it is desiredto-vib'rate any one of the diaphragms 10,.l1or 12, a correspondingseries of waves of electroradiant energy is transmitted, having a wavefrequency equal to the wave frequenc of" the antenna 110, and having aoup,

requency equal to the frequency to w ich the corresponding closed Ioscillatory circuit,"-75,'- 76 or 77 .is tuned.

p These incoming waves of electroradiant energy cause the antenna 110 toset up oscillations in the closed circuit '98, which act permit a unifrequency of the incoming waves, and as this group frequency correspondsonly to .tator 45, 46 or 47.

wave frequencies and' oscillations may be selectively' transmitted,'-thethree series of'transmitted waveshavinig the same wave frequencycorresponding to'the frequency of the receiv-' oup "frequenciesrespectively 'correaplplended claims. and 77 controlling trolled closedcircuits 75, 76 and 77 is tuned, only that closed circuit'will beafi'ected, and oscillationswill be set up in that closed circuit 75, 76or 77 which will cause the operation of the corresponding detector. 70,71 or 72, and thus permit a unidirectional current to'flow throughthe-corresponding controlled circuit 63, 64 or 65 from the correspondingalternator 66, 67 or 68, and energize the corresponding electromagnet60, 61

or 62 to closethe' corresponding circuit40, 41 or 42 through thearmature of the corresponding oscillator 20, 21 or 22, to vibrate thecorresponding diaphragm 10, 11' or 12 accordingly, and to set up soundwaves having a wave frequency equal to the frequency of thecorresponding alternator 43, 44 or 45 and a group frequency equal to thefrequency of the corresponding commu- By simultaneously trans,- mittingtwo or three series of groups of waves of electroradiant energy eachhaving a wave frequency corresponding to the frequency of the antennacircut 110, and having respectively group frequencies equal respectivelyto the frequencies of'tw'o or three of the closed oscillatory circuits75, 76 and 77, a corresponding number of the oscillators 20, 21 and 22may be simultaneously actuated to produce simultaneously correspondingplurality of series of groupsof sound waves having diflerentpredetermined di erent predetermined groupfrequencies respectively.

Although only two of the many forms in which this invention maybe beenshown-herein, it isto be understood that the invention is not limited toany specific construction, but various forms wlthou't spiritof theinvention might'be applied in departingfr'om the or the scope of thethus avin tion, I c aim; I z v 1. The combination with .a plurality ofsound transmitting devices arranged to fully described thisinvenembodied have transmit respectively a plurality of. series ofgroups of sound waves having different wave frequencies and: differentgroup frequencies respectively, of means responsive to radiant energyfor selectively controlling said devices.

2. The combination with a plurality of transmittingd'evices arranged totransmit respectively a plurality of series of groups of compressionalwaves having different wave frequencies and different group frequenciesrespectively, means for *selectively controlling said devices, and"means responsive to radiant energy for actuating said selective means.

3. The combination with a plurality of transmitting devices arrangedv totransmit respectively a plurality ofseries of groups of compressionalwaves having different wave frequencies and different group frequenciesrespectively, means for selectively controlling said devices, and meanscommon to said selective means and responsive to radiant energy foractuating said selective means.

4. The combination with a plurality of transmitting devices arranged totransmit respectively a plurality of series of groups of compressionalwaves having different wave frequencies and different group fre-'quencies respectively separate meansrforr varying the group frequencyof each device, means for selectively controlling said devices, andmeans responsive to radiant energy for actuating said selective means.

5. The combination with a'pIurality of transmitting devices arranged totransmit respectively a plurality of series of compredeterminedfrequency and varied peri odically at a plurality of series of diflerentfrequencies.

Signed at New York in the county of New York and State of New York this6th day'of June A. D. 1917.

J OHN HAYS HAMMOND, J R.

